Formation of delta-doped, buried conducting layers in diamond, by high-energy, B-ion implantation

The electrical properties of a deeply buried, boron-doped layer in type IIa diamond are reported. The layer is fabricated using mega-electron-volt (MeV) B-ion implantation, followed by furnace annealing at 1450 degrees C. Electrical contact to the buried layer is made using laser-induced graphitization. The room temperature Hall mobility of the accepters in the buried layer is 585 cm(2)/Vs, which is the highest value yet reported for ion-implanted diamond, with an acceptor concentration of (3.9 +/- 0.3) x 10(18) cm(-3), a compensation ratio of approximately 5%, and an activation energy of 0.354 +/- 0.006 eV. The temperature dependence of the mobility is very similar to that observed in natural B-doped type IIb diamond. The cap overlying the implanted region, is, following annealing, a high quality, highly insulating diamond, hence opening the possibility of realizing Field Effect Transistor (FET)-type devices in diamond. (C) 1998 Elsevier Science S.A. All rights reserved.